Method of making insulated electrical conductors and the like



Jfine 29 1926. 1,590,599

E. TAYLOR METHOD OF MAKING INSULATED ELECTRICAL CONDUCTORS AND THE LIKE Filed June 17, 1924 f INVENTOR TORNEYS Patented June 29, 1926.

UNITEID'STATIES PATENT OFFICE.

EDWIN TAYLOR, OF BROOKLYN, NEW YORK, ASSIGNOR TO TAYLOR LABORATORIES, INC., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

METHOD OF MAKING INSULATED ELECTRICAL CONDUCTORS AND THE LIKE.

Application filed June 17, 1924. Serial No. 720,520.

.My invention relates to improvements in making insulated electrical conductors and the like. The object of the invention is to provide an electrical conductor with an im- '5 proved insulation of organic material and a method of applying the same in a simple and efficient manner. The invention may also be used for coating other objects than electrical conductors, for example ribbons; sheets, etc., of various materials.

Further and more specific objects, features and advantages will more clearly appear from the detail description, given below taken in connection with the accompanying drawing which forms a part of the specification;

The drawing, partly in vertical section, illustrates more or less diagrammatically an apparatus adapted to put the main features the improvements in one form.

According to my invention in its preferred form, I insulate or coat the conductor or other body with a layer of cellulose. I

preferably do this by making a suitable solug tion of cellulose, applying a layer of this to the wire conductor or other body and removing the solvent constituents from cellulose, leaving a homogeneous integrally continuous layer of cellulose on the body. I preferably remove the solvent constituents by electrolytic action. For this purpose I preferably dissolve the organic material such as cellulosic material in a solution; of zinc chloride or a solution of hydrated cupric oxide in concentrated ammonia. By such solution of the cellulose in zinc chloride or the cupro-ammonia the cellulose is converted from the cellular or fibrous condition to a colloidal state. I preferably use a solution which is relatively concentrated and thick, and apply a suitable layer thereof to the-body to be coated and then subject the cellulose solution on the body to electrolysis whereby the cellulose is deposited more solidly upon the body to be coated which may serve as the anode, and the copper or zinc asthe case may be, is deposited on a cathode, thechlorine or ammonia being given oil in gaseous form. Both the gas so given off, as well as the metal deposited on the cathode, may be recovered for re-use.

Referring *to the drawing which illustrates an apparatus adapted for use in coating or covering rods'or filamentsof celluder pressure, and 9 a pipe for maintaining,

a gas pressure on the contents of tank 10. Through the sidewall of 10 and near the bottom extends a nozzle 12 provided with a definite sized orifice 4, fitted with a perforated guide piece 44, as near the orifice 4 as the choke of the nozzle will permit. Projecting through the opposite wall of the tank 10 is a hollow fitting ornozzle 48, provided with a bore substantially the size of the object to be coated and placed central with the bore of nozzle 12. The nozzle 12 projects through the .wall of a second tank 20, of any desired length, and fitted at its further wall with a stuffing box having a central perforation 47 approximately of the diameter of the coated rod or wire. A vent pipe 33 is placed at the top of tank 20, for

the removal by suction of gases released or,

enerated during operation.

Below the level of the liquid in tank 20, and central with nozzle 12 and stufling box 47, is suspended a tubular electrode 37 split lengthwise to facilitate removal, and provided with electric connections 38, the tube being a cathode while in use. Beyond tank 20 and communicating with it by the stufling box 47 is a third tank 50 containing a roller 48 at its further end.

The object to be coated, for instance a wire 46 on a reel 45, is led through nozzles 43 and 12, through guide piece 44, orifice 4, electrode 37, stuffing box 47 under roller 48, and to a reel 51, situated outside of tank 50 and so driven that it may place the wire under enough tension to draw it from the reel and through the apparatus. Tank 10 is now filled with a viscous, concentrated solution of organic material such as cotton or silk dissolved for example in cupro-ammonia, or in the case of silk in nickel-ammonia alone or in a mixture of both cupro and nickel ammonia. Tank 20 is filled with a dilute acid solution and tank 50 with clean Water. The reel 51 is now started drawing the wire through the apparatus, pressure is applied to tank 10, through pipe 9 causing the cellulose to flow through orifice 4 and an electric current is passed through the wire 46 by means of a contact shoe 28, and a conductor 29, connected to the positive pole of a source of electricity. The wire 46 while passing through the tubular electrode 37, becomes an anode and 37 a cathode. The cellulose issuing between the wall of the orifice 4L and the centrally located wire 46 is caused to flow at a slower speed than the wire and is drawn or stretched thereon in a uniform coating of any desired thickness the flotation effect of the bath materially preventing fiow of the viscous solution after leaving nozzle 12 and before the cellulose has been finally deposited on wire 46 by means of the current passing during the travel of the coated wire through the cathode 37 which is made long enough and the speed of the wire slow enough, to ensure the removal and deposition of the metallic constituent and the release of the gaseous or volatile constituent. After passage through cathode 37 the wire now covered with a rubbery coating of deposited organic material passes through the stuffing box 47 filling the bore thereof and so preventing the water in tank 50 from mixin with the acid liquid in 20 or vice versa. The coated wire 49 is now well washed during passage through tank 50 passes under guide-roll l8, and to reel 51, it now being ready for drying or for further desired operations. It is obvious that in place of one wire or rod passing through orifice 4, any number of wires may be passed in parallel each being separated from its neighbor by coating of cellulose, etc., and the whole enclosed in a like coating of any desired thickness. Furthermore the nozzles and apparatus may be so constructed and placed that a, twisted or cable effect may be imparted to the wires during coating.

The above process after drying, etc., results in a tough, elastic, transparent coating of any thickness or color, etc., desired, firmly adherent to the wire and of a high dielectric strength. Successive coats of the same or different material may be given by passing the covered wire as it leaves tank 50 through successive apparatus of the same kind, the coated wire still wet passing in at a nozzle similar to 4.3 but of larger bore to accommodate the increased diameter.

In the application of this process and its modifications as applied to silk advantage may be taken of the fact that silk will dissolve in nickel ammonia solution, while cotton will not, although cupro-ammonia dissolves both. Mixed silk and cotton waste goods, etc., may be separated and rendered of increased commercial value by first treating the mixed material with nickel-ammonia whereby the silk is dissolved and removed from the cotton by filtration. The cotton may now be dissolved in cupro-ammonia and the silk and cotton solutions either singly or mixed in definite proportions, utilized for coating as above described, with a coating memes filtered and dirt kept out afterward. All

the apparatus should be closed in whereever possible. The Water employed for making up the solutions should be distilled or at any rate contain a minimum of mineral salts and should be free from carbonic acid gas if a fine filament or a perfectly transparent product is desired.

The stren th of the acid water must also be kept wit in reasonable limits although this is easy on account of the large volume in the tank compared to the amount circulated, changes in concentration taking place slowly. This acid water should also be kept free from grosser impurities and from 00 I refer to use nitric acid as its ultimate prod iict under electrolysis is always ammonia. The bath may be kept to strength by the simple addition of nitric acid, the ammonia released from the organic solution or formed by electrolysis being readily drawn from the top of the tanks and directly recovered, and any residual acid easily removed from the cellulose, etc., by washing.-

Definite figures on the electrical current employed are also dificult to give on account of the many variations of the general process. A direct current is preferable; a pulsating current in one direction gives good results but takes a longer time. The prob lem is an electro-chemical one and the rate of deposition of both cellulose and. metal is a function of the amperage rather than of voltage. For instance, in the electrolysis of cellulose dissolved in cupro-ammonia, I have used currents of 110 volts and a current density of 1/2 amp. per sq. inch of anode surface, while almost the same result may be obtained with 1.8 volts and 1/100 of an amp. per sq. inch, although the time required is longer. In general, only enough amperage should be carried to secure a reasonably adherent deposit on the cathode,

of the metallic solution constituent employed. If the current rate is unduly raised, a spongy deposit of metal forms which is apt to fall into the bath, adhere to the material being treated and otherwise cause trouble, while at the same time the bath overheats and more current passes than is required. Contrary to this a heavy amp erage favors the deposition of cellulose. 4 or cathodes a metal similar to the one used in the solvent, copper, nickel, zinc, etc.,.

condition and while adhering well to the cathode, may be easily scraped therefrom in a condition to be readily re-dissolved for the preparation of new solutions.

For dissolving the organic material, cellulose, silk, etc., if the solution is to be an ammoniacal one, I prefer to saturate 30}% ammonia water, free from carbonate of ammonia, etc., with hydrated cupric or nickel oxides. The solutions are filtered through fibrous nitrocellulose, cooled to about 40 F. and saturated with the material to be dissolved in suitable mixing machines. The amount of material dissolved depends largely upon the fiber, etc., used varying somewhat with each difierent quality or grade of the same kind of material. Some raw cottons for instance will completely dis solve in the proportion of 1 lb. cotton to 20 lbs. of cupra, while with other varieties, 1 lb. cotton to 35 lbs. solution is the best that can bedone. When using zinc chloride, I employ a saturated solution of the C. P. salt in distilled water, these solutions being even more sensitive to impurities than the ammonia ones and more difficult to handle and recover.

After solution is complete the viscous mass is allowed to stand for about 24 hours, during which time it becomes much more fluid and may be forced through a filter by means of pressure. A fine sand bed on top of a layer of nitro-cotton, which in turn is supported by a fine wire screen is quite satisfactory. When desired the solutions are now concentrated by centrifugal action.

At this stage other ingredients may be added to the more or less fluid solution. For instance, if a saturated solution of cotton, or other cellulose in cupro-ammonia is employed it is evident that if more cellulose, say in a fibrous but rather finely divided state be added, this latter'addition will be practically unafiected by 'the solution but it will increase the viscosity of the mass, necessitate a higher pressure to force it through the nozzles or dies and will materially reduce'the shrinkage or drying, the result being a material of practically the same chemical composition throughout,

part of which is in the fibrous or cellular H condition and part of which has been solidified from a colloidal condition.

The final layer of organic material with which the body or wire is coated, is substantially non-fibrous and non-cellular in structure, and is substantially homogeneous and continuous.

While I have described my improvements in great detail and with respect to preferred embodiments thereof, I do not desire to be limited to such details and forms, since many changes and modifications may be made and the improvements embodied in widely different forms without departing from the spirit and scope thereof in their broader aspects; hence I desire to cover all forms coming within the language or scope of any one or more of the appended claims. What I claim as new and desire to secure by Letters Patent, is

1. The method of coating bodies with a layer of organic material, which consists in making a solution of the organic mate-. rial,-applying a layer of the solution to the body to be coated, and passing the body through an electrolyte in an electrolytic .cell to remove solvent constituents from the coating electrolytically.

2. The 'method of insulating an electrical conductor, which consists in forming a solution of organic insulating material, applying a layer of the solution to the conductor and subjecting the layer to electrolytic action to remove solvent constituents therefrom. v

3. The method of insulating an electrical conductor which consists in making a solution of cellulosic material, applying a layer of the solution to the conductor, and passing the conductor through an electrolytic cell in which the conductor forms the anode to remove solvent constituents from cellulosic material electrolytically.

4. The method of insulating an electrical conductor which consists in depositing a coating of cellulose on the conductor from a cellulose solution and removing solvent constituents therefrom electrolytically.

5. The method ofcoating bodies with a layer of organic material which consists in passing the body through an electrolytic cell wherein a layer of organic material is electrolyzed on the body.

6. The method of insulating an electrical conductor which consists in passing the conductor through an electrolytic cell wherein a layer of cellulose is electrolyzed on the body from a cellulose solution as it passes through the cell.

7. The method of coating bodies with cellulose which consists in treating the body in an electrolytic cell wherein a layer of cellulose is electrolyzed on the body from a. solution of cellulose.

8. The method of insulating bodies which consists in treating a body in an electrolytic cell wherein a layer of organic insulating material is electrolyzed on the body from a solution of the material to remove solvent constituents by electrolysis.

9. The method of making an insulated electrical conductor wire which consists in passing the. wire through a die, depositing on the wire a layer of a solution of cellulosic material, and then passing the coated wire through an electrolytic cell, with the wire forming the anode of the cell to remove solvent constituents from the layer electrolytically.

10. The method of insulating an electrical conductor wire which consists in passing the Wire through means depositing a layer of a solution of organic insulating material on the wire and subjecting the coated Wire to electrolysis in an electrolytic cell in which the Wire forms the anode.

11. The method Which consists in applying a layer of solution of organic material to a long body, gradually passing the coated body through an electrolytic cell in which the body forms the anode to remove solvent constituents from the layer of organic material electrolytically.

12. The method of insulating an electrical conductor Wire which consists in squirting a solution of cellulose thereon and then subjecting the coating on the Wire in electrolysis to remove solvent constituents from the layer.

In testimony whereof I have signed my name to this specification.

EDWIN TAYLOR. 

